온천수 내 리튬 분포: 국내 심부 지하수환경의 리튬 지화학 연구

Translated title of the contribution: Lithium Distribution in Thermal Groundwater: A Study on Li Geochemistry in South Korean Deep Groundwater Environment

Hyunsoo Seo, Jeong Hwan Lee, Sun Ju Park, Junseop Oh, Jaehoon Choi, Jong Tae Lee, Seong Taek Yun

Research output: Contribution to journalArticlepeer-review

Abstract

The value of lithium has significantly increased due to the rising demand for electric cars and batteries. Lithium is primarily found in pegmatites, hydrothermally altered tuffaceous clays, and continental brines. Globally, groundwater-fed salt lakes and oil field brines are attracting attention as major sources of lithium in continental brines, accounting for about 70% of global lithium production. Recently, deep groundwater, especially geothermal water, is also studied for a potential source of lithium. Lithium concentrations in deep groundwater can increase through substantial water-rock reaction and mixing with brines. For the exploration of lithim in deep groundwater, it is important to understand its origin and behavior. Therefore, based on a nationwide preliminary study on the hydrogeochemical characteristics and evolution of thermal groundwater in South Korea, this study aims to investigate the distribution of lithium in the deep groundwater environment and understand the geochemical factors that affect its concentration. A total of 555 thermal groundwater samples were classified into five hydrochemical types showing distinct hydrogeochemical evolution. To investigate the enrichment mechanism, samples (n = 56) with lithium concentrations exceeding the 90th percentile (0.94 mg/L) were studied in detail. Lithium concentrations varied depending upon the type, with Na(Ca)-Cl type being the highest, followed by Ca(Na)-SO4 type and low-pH Ca(Na)-HCO3 type. In the Ca(Na)-Cl type, lithium enrichment is due to reverse cation exchange due to seawater intrusion. The enrichment of dissolved lithium in the Ca(Na)-SO4 type groundwater occurring in Cretaceous volcanic sedimentary basins is related to the occurrence of hydrothermally altered clay minerals and volcanic activities, while enriched lithium in the low-pH Ca(Na)-HCO3 type groundwater is due to enhanced weathering of basement rocks by ascending deep CO2. This reconnaissance geochemical study provides valuable insights into hydrogeochemical evolution and economic lithium exploration in deep geologic environments.

Translated title of the contributionLithium Distribution in Thermal Groundwater: A Study on Li Geochemistry in South Korean Deep Groundwater Environment
Original languageKorean
Pages (from-to)729-744
Number of pages16
JournalEconomic and Environmental Geology
Volume56
Issue number6
DOIs
Publication statusPublished - 2023 Dec

Bibliographical note

Publisher Copyright:
© 2023 Korean Society of Economic and Environmental Geology. All rights reserved.

ASJC Scopus subject areas

  • Environmental Science (miscellaneous)
  • Geology
  • Economic Geology

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